It has always been desirable to use the strongest possible oxidizing agents as cathodic depolarizers. Some of the strongest, such as CrO.sub.3, however, cannot be used in the most efficient electrochemical systems, ie, those utilizing light active metals such as lithium, sodium, potassium, rubidium, calcium, barium, magnesium and aluminum as such active metals require non-aqueous electrolytes. Such active metals cannot be used with aqueous electrolytes as they are positioned above hydrogen in the electrochemical series and react chemically with aqueous electrolytes instead of electrochemically through the electrolyte. Consequently with such active metal anodes non-aqueous electrolytes are required. Most favored electrolyte systems are those wherein a salt of the anodic metal with highly mobile anions such as perchlorates, hexafluorophosphates, hexafluoroarsenates and tetrafluoroborates are predissolved in non-aqueous polar solvents. Among such solvents commonly used are tetrahydrofuran, propylene carbonate, isopropylamine, dimethoxy ethane, methyl formate, acetonitrile, dimethyl sulfoxide, N-nitrosodimethylamine, dimethyl sulfite, dimethyl formamide, .gamma.-butyrolactone, diethylene glycol and mixtures thereof.
However, CrO.sub.3 and the similar strong oxidizing agents cannot be used as depolarizers for such organic electrolyte electrochemical cells because of the high solubility and chemical reactivity of the depolarizers with the solvents. Until now the main direction for solving this problem has been directed toward finding a solvent/electrolyte system which was sufficiently inert to the depolarizer. However, generally those solvents sufficiently inert to the CrO.sub.3 would not dissolve or ionize sufficient amounts of the electrolyte salts to provide an adequate electrolyte system.